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Solubility is affected by pressure, temperature, and structure.

Pressure

Pressure only affects the solubility of gaseous solutions. Increasing pressure increases gas solubility. The relationship between pressure and solubility is governed by Henry’s law: C = kP. C is the concentration of dissolved gas, k is the Henry’s Law constant, and P is the temperature.

Sample calculations for Henry’s Law (Part of the Solubility factors page) Okay, so we are going to run you through some easy calculations using Henry’s Law. We are going to calculate the Henry’s law constant k for a substance that you encounter in everyday life, carbon dioxide. So Galen Lew the Science Dude blew some carbon dioxide into a cup of water. He blew it so hard that the carbon dioxide became dissolved in the water. Galen Lew figured he blew in about 0.425 mol/L of carbon dioxide. When we used the barometer to see wat the partial pressure was, we got a reading of 12.5 atm, which is pretty high. You are given the two most important things you need for solving this problem: the concentration of dissolved substance, and partial pressure. 0.425 M and 12.5 atm Basically, you plug these two values into the Henry’s law equation C = k x P 0.425 M = k x 12.5 atm k = 0.34 mols x atm / L Temperature At higher temperatures, solubility generally increases. This tends to vary depending on whether the solution is endothermic or exothermic. For the former, increasing temperature increases solubility. This happens because For gases, however, it’s the opposite; the solubility of gases decreases with temperature. So why is this? As temperature increases, the kinetic energy of the solute molecules increases, causing them to escape from solution. Conversely, kinetic energy of the solute molecules decrease as temperature goes down. These slowed down molecules are less likely to break away from the solution.

Structure

Like dissolves like. Solutes and solvents that have similar polarities are more likely to be soluble.

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